In English, we say "practice makes perfect" to indicate that practice of a skill leads to mastery. So a Latin teacher might attempt to inspire a student to diligence by saying "Write out these declensions 50 times. Practice makes perfect."
What is an idiomatic way of saying this phrase in Latin, preferably Classical Latin? I notice that Wikipedia lists a phrase, usus est magister optimus, to mean this, but a search for that phrase in the Classical corpus comes back with nothing. Is this the best option available?